The present invention is a device which secures trucks and other vehicles to a loading dock during loading and unloading, or during overnight stays. As professionals working with such vehicles understand, chocking the wheels is simply not enough to prevent serious loading and unloading accidents, ice slide casualties, or trailer draft. The restraining device of the present invention prevents the vehicle from creeping, thereby making the vehicle and dock one stable platform. The present invention is a simple mechanical device, which reduces operator confusion during operation, maintenance, and repair.
Many truck restraints have been developed to lock and secure the ICC bar of a truck or other vehicle to a dock wall. These restraints may be divided into two basic groups, powered and non-powered. The powered restraints are generally run by electricity or hydraulics. The non-powered restraints are generally controlled manually. Within the patent literature, such mechanical devices are represented by U.S. Pat. No. 5,026,242 (Alexander).
U.S. Pat. No. 5,026,242 teaches a device that is actuated when the vehicle ICC bar moves an arm of the restraint. Using a cam follower and a spring system, a restraining member is raised using the motion of the arm to transfer energy thereby raising the restraint. Such an arrangement has a serious disadvantage. Weakening of the spring will affect operation of the device. Also, the arm engaging the ICC bar must be relatively long to accommodate variations in truck height.
Electrical and hydraulic devices are represented in U.S. Pat. No. 4,488,325 (Bennett, et al.), U.S. Pat. No. 4,664,582 (Edmeads), U.S. Pat. No. 4,767,254 (Kovach, et al.), U.S. Pat. No. 4,784,567 (Hageman, et al.), U.S. Pat. No. 4,887,954 (Gregerson, et al.), U.S. Pat. No. 4,915,568 (West) and U.S. Pat. No. 5,071,306 (Alexander).
U.S. Pat. No. 4,488,325 (Bennett, et al.) teaches a device in which a frame is mounted on the front surface of a dock beneath a pit which houses an adjustable dockboard. To raise or lower the slide assembly, a motor, mounted on the slide assembly, drives a gear that engages a rack carried by the frame. Unfortunately, the motor may be inoperable if electricity is not available, thereby causing the device to fail.
The Edmeads device of U.S. Pat. No. 4,664,582 includes a drive cylinder that is attached to a base plate and a carriage plate and effects longitudinal travel of the carriage plate. Here, the hook will disengage if there is a failure of hydraulic pressure.
The device of U.S. Pat. No. 4,767,254 (Kovach) includes a restraining member which is biased upwardly to an operative position. A power operated unit is arranged to move the restraining member downwardly from the operative position to a storage position where it is locked by a releasable latch. The disadvantage of the Kovach device is that the restraining member may be inoperable if electricity is unavailable.
U.S. Pat. No. 4,784,567 (Hageman, et al.) teaches a device which encompasses a hook that is moved between an operative and an inoperative position by a fluid cylinder assembly. The cylinder herein is disposed in a recess in the driveway adjacent to the loading dock. The piston rod of the fluid cylinder assembly is connected to the hook. A disadvantage of this device is that the hook will disengage if there is a failure of hydraulic pressure.
The Gregerson device of U.S. Pat. No. 4,887,954 teaches a sector assembly which is mounted within a frame and rotates about a substantially horizontal axis. An actuator connected to the frame and sector assembly rotates the sector assembly in a first rotational direction to a restraint position in which the vehicle is locked to the adjacent structure. The assembly rotates in an opposite rotational direction to a release position in which the vehicle is released. The disadvantage of this device lies in the fact that the hook will be inoperable if the pneumatic lines freeze due to moisture.
The truck restraining apparatus of U.S. Pat. No. 4,915,568 (West) has a vertically extending jackscrew to which a follower nut is mounted. The jackscrew passes through a bore in a restraining member and is held in position by brackets on a mounting plate. Means, such as an electric motor, are provided for rotation of the jackscrew. Unfortunately, the motor and device may be inoperable if electricity is unavailable.
In the Alexander device of U.S. Pat. No. 5,071,306, all loading on the restraining device is transmitted to the frame while the device is in the vehicle restraining position since there is no force component on the actuator. A pair of switches may be used to determine whether the actuating member is either in its fully extended vehicle restraining position. As will be understood, the device will become inoperable if power is unavailable.
Accordingly, it is the general object of the present invention to provide a vehicle restraining device which requires no outside source of power. A further object of the invention is to provide a simple mechanical vehicle restraining device which can be easily installed. Yet another object of the invention is to provide a vehicle restraining device which will be simple to maintain. Other objects and features will be in part apparent and in part pointed out hereinafter.